Vitamin A and its derivatives (retinoids) have great potential as chemoprevention agents against various epithelial malignancies, including skin cancer. Over the past two years, we have been testing the hypothesis that retinoids can decrease the number of new skin cancers (basal cell carcinoma, squamous cell carcinoma) in patients at great risk, namely those with eight or greater previous cutaneous cancers. To this end, 110 participants have thus far been enrolled in a three year, three arm randomized double-blind study comparing the effects of retinol (25,000 units per day) vs. 13-cis retinoic acid (.15 mg/kg/day) vs. placebo on the incidence of subsequent cutaneous malignancies, as well as the rate of protocol compliance and the types and degree of toxicity. A total accrural of 411 patients is expected and should be achieved by June 1988.